It's not a big lead, or even one outside of the margin of error, but it's a lead. And it's from a reputable non-partisan pollster (.pdf):

According to the most recent poll by Fairleigh Dickinson University's PublicMind, Democratic incumbent Jon Corzine edges Republican challenger Chris Christie 44% to 43% among likely voters in the race for New Jersey governor.  Another 4% volunteer they will vote for independent Chris Daggett and 5% say they are undecided.  "With the start of an advertising blitz and the raw exposure of the debate, the race has tightened to a dead heat," said Peter Woolley, a political scientist and director of the poll.

With Independent Chris Daggett's name included in the poll (rather than being open to be volunteered by respondents), Democrat Jon Corzine holds a similar 1-point lead over Republican Chris Christie, 38 percent to 37 percent, with 17 percent backing Daggett.

The numbers from this poll don't mean that Corzine is now on the inside track to reelection, or that he necessarily has much of a genuine lead. What they do confirm, however, is what he have known now for months: That Corzine has the momentum as Christie continues to sink badly. What's more, as I noted last week, considering that pre-election polling in New Jersey has consistently underestimated support for Democratic candidates -- in the 2002 Senate campaign, in the 2004 presidential campaign, in the 2005 gubernatorial campaign, and in the 2006 Senate campaign -- the fact that Corzine has now caught up with Christie in this polling means that the Democrat has a much greater shot at victory in this race than at virtually any other previous point in this campaign. And even if you gave me some odds, I'm not sure that at this point I'd put any money on Christie to eek out a victory.